1. Field of the Invention
The present invention lies in the field of hydraulic pressure accumulators.
2. The Prior Art
Pressure accumulators or dampeners are currently in widespread use in areas where energy storage and/or dampening of pulses in a hydraulic system are desired. As is well known, a form of accumulator includes a rigid pressure vessel, generally in the form of a cylinder having rounded upper and lower ends. In the upper end there is typically provided a gas charging port, the lower end having formed therein an oil port.
A resiliently distensible bladder member is suspended within the pressure vessel, dividing the same into two discrete chambers communicating, respectively, with the oil port and the gas charging port.
In use, the oil port is connected to a source of fluid under pressure, e.g. the hydraulic line emerging from a pump.
Gas under pressure is introduced into the other chamber. Where the pressure in the hydraulic line is less than the pressure in the gas chamber, the bladder is expanded and seals the oil port, a valve member being typically provided on the bladder to reduce wear on the bladder walls.
When the pressure in the line carrying the oil (or other liquid) exceeds the pressure in the bladder, the gas in the chamber communicating with the gas charging port is compressed and the valve is unseated, allowing the flow of liquid through the oil port into the interior of the pressure vessel.
Since pressure vessels comprise rigid metallic members, it is impossible to inspect the interior thereof to establish the condition of the bladder without disassembly of the accumulator apparatus.
While in some applications, malfunction of the accumulator, as resulting from rupture of the bladder for instance, may be readily detected by the sensing of changed operating conditions, in other situations, i.e. where a plurality of accumulators are used in a system as pulse dampeners, bladder failure of a given accumulator will not be evident. Moreover, accumulators are often located at positions remote from the control unit or area, i.e. at widely spaced intervals along an oil conduit, and determination of bladder failure requires an on-sight inspection of the device.